c++Unicode、UTF8、ANSI 字符串转换

string qUnicodeToAnsi(wstring &buf)
{
int len = ::WideCharToMultiByte(CP_ACP, 0, buf.data(), buf.size(), NULL, 0, NULL, NULL);
if (len == 0) return “”;

std::vector utf8(len);
len = ::WideCharToMultiByte(CP_ACP, 0, buf.data(), buf.size(), &utf8[0], len, NULL, NULL);

return string(&utf8[0],len);

}

wstring qAnsiToUnicode(string &buf)
{
int len = ::MultiByteToWideChar(CP_ACP, 0, buf.data(), buf.size(), NULL, 0);
if (len == 0) return L"";

std::vector unicode(len);
len = ::MultiByteToWideChar(CP_ACP, 0, buf.data(), buf.size(), &unicode[0], len);
return wstring(&unicode[0],len);

}

wstring qUtf8ToUnicode(string &buf)
{
int len = ::MultiByteToWideChar(CP_UTF8, 0, buf.data(), buf.size(), NULL, 0);
if (len == 0) return L"";

std::vector unicode(len);
len = ::MultiByteToWideChar(CP_UTF8, 0, buf.data(), buf.size(), &unicode[0], len);

return wstring(&unicode[0],len);

}

string qUnicodeToUtf8(wstring &buf)
{
int len = ::WideCharToMultiByte(CP_UTF8, 0, buf.data(), buf.size(), NULL, 0, NULL, NULL);
if (len == 0) return “”;

std::vector utf8(len);
len = ::WideCharToMultiByte(CP_UTF8, 0, buf.data(), buf.size(), &utf8[0], len, NULL, NULL);

return string(&utf8[0],len);

}